package upload

import (
	"context"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	"qnc-server/app/main/api/internal/svc"
	"qnc-server/common/xerr"

	"github.com/pkg/errors"
	"github.com/zeromicro/go-zero/core/logx"
)

type ServeUploadLogic struct {
	logx.Logger
	ctx    context.Context
	svcCtx *svc.ServiceContext
}

func NewServeUploadLogic(ctx context.Context, svcCtx *svc.ServiceContext) *ServeUploadLogic {
	return &ServeUploadLogic{
		Logger: logx.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx,
	}
}

func (l *ServeUploadLogic) ServeUpload(name string, w http.ResponseWriter) error {
	name = filepath.Base(strings.TrimSpace(name))
	if name == "" || name == "." || name == ".." || !isSafeUploadFileName(name) {
		return errors.Wrapf(xerr.NewErrMsg("无效的文件名"), "")
	}
	fullPath := filepath.Join(uploadImageDir, name)
	data, err := os.ReadFile(fullPath)
	if err != nil {
		if os.IsNotExist(err) {
			return errors.Wrapf(xerr.NewErrMsg("文件不存在"), "")
		}
		return errors.Wrapf(xerr.NewErrCode(xerr.SERVER_COMMON_ERROR), "读取文件失败: %v", err)
	}
	w.Header().Set("Cache-Control", "public, max-age=86400")
	switch filepath.Ext(name) {
	case ".png":
		w.Header().Set("Content-Type", "image/png")
	case ".gif":
		w.Header().Set("Content-Type", "image/gif")
	case ".webp":
		w.Header().Set("Content-Type", "image/webp")
	default:
		w.Header().Set("Content-Type", "image/jpeg")
	}
	_, err = w.Write(data)
	return err
}

func isSafeUploadFileName(name string) bool {
	for _, c := range name {
		if (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || c == '.' || c == '_' || c == '-' {
			continue
		}
		return false
	}
	return true
}